1. Field of the Invention
The present invention relates to laser processing machines which can process sheet-like workpieces such as sheet metals by various methods such as cutting and piercing by use of laser beams produced by laser resonators.
2. Description of the Prior Art
As is well-known, a laser beam is widely used in industries to process a variety of metallic and nonmetallic materials such as irons, nickels, plastics, rubbers and glasses.
Generally, a laser processing machine comprises a laser generator for generating the laser beam and a laser beam cutting machine having a processing head assembly to apply and focus the laser beam from the laser generator. The laser beam cutting machine has a work-table and workpiece positioning means on the work-table.
Heretofore, however, in a laser processing machine of the above-described type, the laser generator and the laser beam cutting machine are indpendent construction, as evidenced for example by the disclosures in U.S. Pat. No. 4,088,865 entitled "Laser Beam Welding Apparatus", filed on Jan. 2, 1976. Therefore, the laser beam from the generator is directed through a complicated mirror assembly to the laser beam cutting machine. This arrangement is considered to cause for an optical center deviation of the laser beam. The optical center deviation are arised by a thermal deformation of the mirror assembly and the different vibration between the laser generator and the laser beam cutting machine. Thus, the maintenance and adjustments of the mirror assembly are required and they involves considerable time and handling.
Furthermore, in order to perform an accurate and fine processing for producing intricate shape products, it is necessary to exactly adjust the workpiece positioning means according to predetermined procedure. However, it is sometimes difficult for operating personnel to make the exact and complex adjustment. It has been also conventionally disadvantageous that the laser processing machines are not provided with a scaling or enlarging function mechanism in a cutting shape. Thus, when the scaling or enlarging process is required, operating personnel have to load the geometric data of the workpiece to be cut to a control device.
Furthermore in a conventional laser processing machine, a focus point of the laser beam is set slightly under the top surface of any workpiece with the same thickness. Therefore, when the laser processing condition is changed, for example, from cutting to piercing, it is extremely difficult to perform an accurate and fine processing.